Morris Minor Owners Club

Ok call me, stupid, young, inexperianced, an ideot, ok....don't, but... what precisly are you measuring with this vaccum contraption, and what else can you measure from your moggy??? I mean, there can't be that much, can you get a fual consumption gauge?? Our BMW had one but I dunno if you fix them in after that car has been built?

The vacuum gauge measures vacuum generated by your engine. When the engine is purring away it draws air/fuel mix through the carb and into the cylinders, this creates a vacuum as you increase speed the air/fuel mix is 'forced' through the carb much faster and so creates a greater vacuum! This diffence in vacuum with speed is essential for the time at which the fuel/air mixture ignites. There is a pipe (a thin one on our cars) which is tapped off the carb and goes to the mushroom thing attached to the distributor - inside this mushroom (sorry for the non-technical term) are some weights and I do believe that as the engine revs i.e. driving down the motorway the increase in vacuum pulls these weights and so moves the points inside the distributor and alters the time of ignition????? (I'm going to be slated on my flawed explanantion) but anyway, this vacuum gauge is a sort of efficiency device that measures how well a vacuum is achieved in the mushroom thingy and so determins if fuel is burning efficient. I'm sorry but if my car was to be assimilated by the borg then they would just larf at the poor efficiency!

Also you can measure temperature (by attaching a capillary tube to the hole on the head - its covered by a blanking bolt or you can raid a metro/maestro/mini for an electronic sensor for a electronic gauge.

You can have an oil pressure gauge - once again a tube from the by-pass to the oil filter pot to the gauge (about £13 altogether) or once again electronic. And you can have a 12v car clock. All can be found on eBay but be careful and read the small print to see if it works in the first place before you buy.

Cam has many more gauges than I do so take a look on his website - it's a good read

I'll shut up now......

Msg to cam:

No i left all pipes lolling around like bladders on sticks. I didn't cover any holes! Can I rectify the prob? Oh and the deal with the chuggin sound - (sorry but I'm cowering in the corner, i forgot to put the spark plug back on after I cut the advance pipe........

I've finally done it, Ive uploaded a picture of my speaker(s) , if you cant guess , they are in the side panels above the parcel tray, i used the backing of a chest of draws ( the ply wood board thingy ) so ive got plush speakers but destroyed the chest of draws . see picture below

Pidge ( PDG457G ) and lee

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bladders on sticks

Ha ha, I like that!!

There's no problem, if you say that the chug was a missing lead!

Nice speaker pods!

I seem however still register a 'poor' reading on the gauge!

Those look like the same speakers as I've got (10cm 2.5mounting depth) - why did you need the pods? There's enough room back there, surely? Have to say, they do look fab though!

I seem however still register a 'poor' reading on the gauge!

What is your gauge calibrated in?? inches of mercury? If so, then if you can tell me what it is reading (at tickover), then I can tell if it's too low.

A low reading means that either you have a VERY tuned engine or you have an air leak somewhere.

When you put your foot down the gauge should read zero and when decelerating it should read high

Gareth - I found that the magnet on the speakers kept vibrating against the body, also I wanted them to be more pronounced.

Cam - The pressure is measured in inches of mercury, when the car is ticking over the reading is more or less 0! When i accelerate is does climb but hasn't gone over 10 in/Hg

Right, it sounds like you either have a faulty gauge, dodgy connection or an air leak.

My gauge reads from 0 to 30 INS/Hg



When it is ticking over it reads about 15. When under full throttle it reads zero, and when decelerating it reads about 20-25.

Your reading should not climb under acceleration as the butterfly is open more so the vacuum felt should be a lot lower, not higher. There is something wrong there!

When the car is on idle the needle remains at zero, on acceleration the needle climbs up to no more than 5"/Hg and on deceleration it gives a similar reading! Do you think its an air leak?

The needle should not climb on acceleration as the vacuum reduces in the inlet manifold.

Maybe: If there is a leak so that at tickover there is no neg pressure registering then on gradual acceleration maybe there is more pull due to the higher rpm. I'm just guessing there, but it's not right at all.

Yes, I would definately start looking for air leaks around the inlet manifold, carb, vacuum pipes and advance unit.

Ok - Me thinks the old 'trying to find a puncture' method might show where a leak might be.....I'll keep you posted! Thanx for the help though!

at last ive finally got a picture of my gauges, it not quite as many as Cam but I will have room for improvement

an_avenger

Tastefully done, mate!